1
|
Moir RD, Merheb E, Chitu V, Richard Stanley E, Willis IM. Molecular basis of neurodegeneration in a mouse model of Polr3-related disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.12.571310. [PMID: 38168294 PMCID: PMC10760057 DOI: 10.1101/2023.12.12.571310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Pathogenic variants in subunits of RNA polymerase (Pol) III cause a spectrum of Polr3-related neurodegenerative diseases including 4H leukodystrophy. Disease onset occurs from infancy to early adulthood and is associated with a variable range and severity of neurological and non-neurological features. The molecular basis of Polr3-related disease pathogenesis is unknown. We developed a postnatal whole-body mouse model expressing pathogenic Polr3a mutations to examine the molecular mechanisms by which reduced Pol III transcription results primarily in central nervous system phenotypes. Polr3a mutant mice exhibit behavioral deficits, cerebral pathology and exocrine pancreatic atrophy. Transcriptome and immunohistochemistry analyses of cerebra during disease progression show a reduction in most Pol III transcripts, induction of innate immune and integrated stress responses and cell type-specific gene expression changes reflecting neuron and oligodendrocyte loss and microglial activation. Earlier in the disease when integrated stress and innate immune responses are minimally induced, mature tRNA sequencing revealed a global reduction in tRNA levels and an altered tRNA profile but no changes in other Pol III transcripts. Thus, changes in the size and/or composition of the tRNA pool have a causal role in disease initiation. Our findings reveal different tissue- and brain region-specific sensitivities to a defect in Pol III transcription.
Collapse
Affiliation(s)
- Robyn D. Moir
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - Emilio Merheb
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - Violeta Chitu
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - E. Richard Stanley
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - Ian M. Willis
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| |
Collapse
|
2
|
McGirr T, Onar O, Jafarnejad SM. Dysregulated ribosome quality control in human diseases. FEBS J 2024. [PMID: 38949989 DOI: 10.1111/febs.17217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 05/31/2024] [Accepted: 06/20/2024] [Indexed: 07/03/2024]
Abstract
Precise regulation of mRNA translation is of fundamental importance for maintaining homeostasis. Conversely, dysregulated general or transcript-specific translation, as well as abnormal translation events, have been linked to a multitude of diseases. However, driven by the misconception that the transient nature of mRNAs renders their abnormalities inconsequential, the importance of mechanisms that monitor the quality and fidelity of the translation process has been largely overlooked. In recent years, there has been a dramatic shift in this paradigm, evidenced by several seminal discoveries on the role of a key mechanism in monitoring the quality of mRNA translation - namely, Ribosome Quality Control (RQC) - in the maintenance of homeostasis and the prevention of diseases. Here, we will review recent advances in the field and emphasize the biological significance of the RQC mechanism, particularly its implications in human diseases.
Collapse
Affiliation(s)
- Tom McGirr
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK
| | - Okan Onar
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK
- Department of Biology, Faculty of Science, Ankara University, Turkey
| | | |
Collapse
|
3
|
Kapur M, Molumby MJ, Guzman C, Heinz S, Ackerman SL. Cell-type-specific expression of tRNAs in the brain regulates cellular homeostasis. Neuron 2024; 112:1397-1415.e6. [PMID: 38377989 PMCID: PMC11065635 DOI: 10.1016/j.neuron.2024.01.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 12/23/2023] [Accepted: 01/29/2024] [Indexed: 02/22/2024]
Abstract
Defects in tRNA biogenesis are associated with multiple neurological disorders, yet our understanding of these diseases has been hampered by an inability to determine tRNA expression in individual cell types within a complex tissue. Here, we developed a mouse model in which RNA polymerase III is conditionally epitope tagged in a Cre-dependent manner, allowing us to accurately profile tRNA expression in any cell type in vivo. We investigated tRNA expression in diverse nervous system cell types, revealing dramatic heterogeneity in the expression of tRNA genes between populations. We found that while maintenance of levels of tRNA isoacceptor families is critical for cellular homeostasis, neurons are differentially vulnerable to insults to distinct tRNA isoacceptor families. Cell-type-specific translatome analysis suggests that the balance between tRNA availability and codon demand may underlie such differential resilience. Our work provides a platform for investigating the complexities of mRNA translation and tRNA biology in the brain.
Collapse
Affiliation(s)
- Mridu Kapur
- Department of Cellular and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA; The Howard Hughes Medical Institute
| | - Michael J Molumby
- Department of Cellular and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA; The Howard Hughes Medical Institute
| | - Carlos Guzman
- Department of Medicine, Division of Endocrinology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Bioengineering, Bioinformatics & Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sven Heinz
- Department of Medicine, Division of Endocrinology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Bioengineering, Bioinformatics & Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan L Ackerman
- Department of Cellular and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA; The Howard Hughes Medical Institute; Department of Neurobiology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
| |
Collapse
|
4
|
Ryoo HD. The integrated stress response in metabolic adaptation. J Biol Chem 2024; 300:107151. [PMID: 38462161 PMCID: PMC10998230 DOI: 10.1016/j.jbc.2024.107151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 02/28/2024] [Accepted: 03/03/2024] [Indexed: 03/12/2024] Open
Abstract
The integrated stress response (ISR) refers to signaling pathways initiated by stress-activated eIF2α kinases. Distinct eIF2α kinases respond to different stress signals, including amino acid deprivation and mitochondrial stress. Such stress-induced eIF2α phosphorylation attenuates general mRNA translation and, at the same time, stimulates the preferential translation of specific downstream factors to orchestrate an adaptive gene expression program. In recent years, there have been significant new advances in our understanding of ISR during metabolic stress adaptation. Here, I discuss those advances, reviewing among others the ISR activation mechanisms in response to amino acid deprivation and mitochondrial stress. In addition, I review how ISR regulates the amino acid metabolic pathways and how changes in the ISR impact the physiology and pathology of various disease models.
Collapse
Affiliation(s)
- Hyung Don Ryoo
- Department of Cell Biology, New York University Grossman School of Medicine, New York, New York, USA.
| |
Collapse
|
5
|
Salpietro V, Maroofian R, Zaki MS, Wangen J, Ciolfi A, Barresi S, Efthymiou S, Lamaze A, Aughey GN, Al Mutairi F, Rad A, Rocca C, Calì E, Accogli A, Zara F, Striano P, Mojarrad M, Tariq H, Giacopuzzi E, Taylor JC, Oprea G, Skrahina V, Rehman KU, Abd Elmaksoud M, Bassiony M, El Said HG, Abdel-Hamid MS, Al Shalan M, Seo G, Kim S, Lee H, Khang R, Issa MY, Elbendary HM, Rafat K, Marinakis NM, Traeger-Synodinos J, Ververi A, Sourmpi M, Eslahi A, Khadivi Zand F, Beiraghi Toosi M, Babaei M, Jackson A, Bertoli-Avella A, Pagnamenta AT, Niceta M, Battini R, Corsello A, Leoni C, Chiarelli F, Dallapiccola B, Faqeih EA, Tallur KK, Alfadhel M, Alobeid E, Maddirevula S, Mankad K, Banka S, Ghayoor-Karimiani E, Tartaglia M, Chung WK, Green R, Alkuraya FS, Jepson JEC, Houlden H. Bi-allelic genetic variants in the translational GTPases GTPBP1 and GTPBP2 cause a distinct identical neurodevelopmental syndrome. Am J Hum Genet 2024; 111:200-210. [PMID: 38118446 PMCID: PMC10806450 DOI: 10.1016/j.ajhg.2023.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 12/22/2023] Open
Abstract
The homologous genes GTPBP1 and GTPBP2 encode GTP-binding proteins 1 and 2, which are involved in ribosomal homeostasis. Pathogenic variants in GTPBP2 were recently shown to be an ultra-rare cause of neurodegenerative or neurodevelopmental disorders (NDDs). Until now, no human phenotype has been linked to GTPBP1. Here, we describe individuals carrying bi-allelic GTPBP1 variants that display an identical phenotype with GTPBP2 and characterize the overall spectrum of GTP-binding protein (1/2)-related disorders. In this study, 20 individuals from 16 families with distinct NDDs and syndromic facial features were investigated by whole-exome (WES) or whole-genome (WGS) sequencing. To assess the functional impact of the identified genetic variants, semi-quantitative PCR, western blot, and ribosome profiling assays were performed in fibroblasts from affected individuals. We also investigated the effect of reducing expression of CG2017, an ortholog of human GTPBP1/2, in the fruit fly Drosophila melanogaster. Individuals with bi-allelic GTPBP1 or GTPBP2 variants presented with microcephaly, profound neurodevelopmental impairment, pathognomonic craniofacial features, and ectodermal defects. Abnormal vision and/or hearing, progressive spasticity, choreoathetoid movements, refractory epilepsy, and brain atrophy were part of the core phenotype of this syndrome. Cell line studies identified a loss-of-function (LoF) impact of the disease-associated variants but no significant abnormalities on ribosome profiling. Reduced expression of CG2017 isoforms was associated with locomotor impairment in Drosophila. In conclusion, bi-allelic GTPBP1 and GTPBP2 LoF variants cause an identical, distinct neurodevelopmental syndrome. Mutant CG2017 knockout flies display motor impairment, highlighting the conserved role for GTP-binding proteins in CNS development across species.
Collapse
Affiliation(s)
- Vincenzo Salpietro
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Reza Maroofian
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Maha S Zaki
- Department of Clinical Genetics, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Jamie Wangen
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Andrea Ciolfi
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Sabina Barresi
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Stephanie Efthymiou
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Angelique Lamaze
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms University, Münster, Germany
| | - Gabriel N Aughey
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Fuad Al Mutairi
- Genetic and Precision Medicine Department, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia; King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | | | - Clarissa Rocca
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Elisa Calì
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Andrea Accogli
- Division of Medical Genetics, Department of Pediatrics, McGill University, Montreal, Canada
| | - Federico Zara
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, Genoa, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy; Unit of Pediatric Neurology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Majid Mojarrad
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Huma Tariq
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Edoardo Giacopuzzi
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK; Genomics Research Centre, Human Technopole, Milan, Italy; Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Jenny C Taylor
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | | | | | | | - Marwa Abd Elmaksoud
- Neurology Unit, Department of Pediatrics, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Mahmoud Bassiony
- Faculty of Medicine, University of Alexandria, Alexandria, Egypt
| | - Huda G El Said
- Department of Family Health, High Institute of Public Health, University of Alexandria, Alexandria, Egypt
| | - Mohamed S Abdel-Hamid
- Department of Medical Molecular Genetics, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Maha Al Shalan
- Genetic and Precision Medicine Department, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia; King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | | | | | - Hane Lee
- 3billion, Inc, Seoul, South Korea
| | | | - Mahmoud Y Issa
- Department of Clinical Genetics, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Hasnaa M Elbendary
- Department of Clinical Genetics, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Karima Rafat
- Department of Clinical Genetics, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Nikolaos M Marinakis
- Laboratory of Medical Genetics, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Joanne Traeger-Synodinos
- Laboratory of Medical Genetics, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Athina Ververi
- Genetics Unit, Department of Obstetrics & Gynaecology, Aristotle University of Thessaloniki, Papageorgiou General Hospital, Thessaloniki, Greece
| | | | - Atieh Eslahi
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Masshad, Iran; Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Masshad, Iran
| | | | - Mehran Beiraghi Toosi
- Pediatric Neurology Department, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Meisam Babaei
- Department of Pediatrics, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Adam Jackson
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester M13 9WL, UK
| | | | | | - Marcello Niceta
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Roberta Battini
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, 56128 Pisa, Italy; Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Antonio Corsello
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Chiara Leoni
- Center for Rare Diseases and Birth Defects, Department of Women and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | | | - Bruno Dallapiccola
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Eissa Ali Faqeih
- Unit of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | | | - Majid Alfadhel
- Genetic and Precision Medicine Department, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia; King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia; College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
| | - Eman Alobeid
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Sateesh Maddirevula
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Kshitij Mankad
- Department of Neuroradiology, Great Ormond Street Hospital, London, UK
| | - Siddharth Banka
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester M13 9WL, UK
| | - Ehsan Ghayoor-Karimiani
- Genetics Research Centre, Molecular and Clinical Sciences Institute, University of London, St George's, Cranmer Terrace, London SW17 0RE, UK
| | - Marco Tartaglia
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Wendy K Chung
- Department of Pediatrics, Boston Children's Hospital Harvard Medical School, Boston, MA 02115, USA
| | - Rachel Green
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - James E C Jepson
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK.
| |
Collapse
|
6
|
Meydan S, Guydosh NR. Is there a localized role for translational quality control? RNA (NEW YORK, N.Y.) 2023; 29:1623-1643. [PMID: 37582617 PMCID: PMC10578494 DOI: 10.1261/rna.079683.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023]
Abstract
It is known that mRNAs and the machinery that translates them are not uniformly distributed throughout the cytoplasm. As a result, the expression of some genes is localized to particular parts of the cell and this makes it possible to carry out important activities, such as growth and signaling, in three-dimensional space. However, the functions of localized gene expression are not fully understood, and the underlying mechanisms that enable localized expression have not been determined in many cases. One consideration that could help in addressing these challenges is the role of quality control (QC) mechanisms that monitor translating ribosomes. On a global level, QC pathways are critical for detecting aberrant translation events, such as a ribosome that stalls while translating, and responding by activating stress pathways and resolving problematic ribosomes and mRNAs at the molecular level. However, it is unclear how these pathways, even when uniformly active throughout the cell, affect local translation. Importantly, some QC pathways have themselves been reported to be enriched in the proximity of particular organelles, but the extent of such localized activity remains largely unknown. Here, we describe the major QC pathways and review studies that have begun to explore their roles in localized translation. Given the limited data in this area, we also pose broad questions about the possibilities and limitations for how QC pathways could facilitate localized gene expression in the cell with the goal of offering ideas for future experimentation.
Collapse
Affiliation(s)
- Sezen Meydan
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
- National Institute of General Medical Sciences, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Nicholas R Guydosh
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| |
Collapse
|
7
|
Luo S, Alwattar B, Li Q, Bora K, Blomfield AK, Lin J, Fulton A, Chen J, Agrawal PB. Genetic deficiency of ribosomal rescue factor HBS1L causes retinal dystrophy associated with Pelota and EDF1 depletion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.18.562924. [PMID: 37905068 PMCID: PMC10614867 DOI: 10.1101/2023.10.18.562924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Inherited retinal diseases (IRDs) encompass a genetically diverse group of conditions in which mutations in genes critical to retinal function lead to progressive loss of photoreceptor cells and subsequent visual impairment. A handful of ribosome-associated genes have been implicated in retinal disorders alongside neurological phenotypes. This study focuses on the HBS1L gene, encoding HBS1 Like Translational GTPase which has been recognized as a critical ribosomal rescue factor. Previously, we have reported a female child carrying biallelic HBS1L mutations, manifesting growth restriction, developmental delay, and hypotonia. In this study, we describe her ophthalmologic findings, compare them with the Hbs1ltm1a/tm1a hypomorph mouse model, and evaluate the underlying microscopic and molecular perturbations. The patient was noted to have impaired visual function observed by electroretinogram (ERG), with dampened amplitudes of a- and b-waves in both rod- and cone-mediated responses. Hbs1ltm1a/tm1a mice exhibited profound retinal thinning of the entire retina, specifically of the outer retinal photoreceptor layer, detected using in vivo imaging of optical coherence tomography (OCT) and retinal cross sections. TUNEL assay revealed retinal degeneration due to extensive photoreceptor cell apoptosis. Loss of HBS1L resulted in comprehensive proteomic alterations in mass spectrometry analysis, with169 proteins increased and 480 proteins decreased including many critical IRD-related proteins. GO biological process and GSEA analyses reveal that these downregulated proteins are primarily involved in photoreceptor cell development, cilium assembly, phototransduction, and aerobic respiration. Furthermore, apart from the diminished level of PELO, a known partner protein, HBS1L depletion was accompanied by reduction in translation machinery associated 7 homolog (Tma7), and Endothelial differentiation-related factor 1(Edf1) proteins, the latter of which coordinates cellular responses to ribosome collisions. This novel connection between HBS1L and ribosome collision sensor (EDF1) further highlights the intricate mechanisms underpinning ribosomal rescue and quality control that are essential to maintain homeostasis of key proteins of retinal health, such as rhodopsin.
Collapse
Affiliation(s)
- Shiyu Luo
- Division of Neonatology, Department of Pediatrics, University of Miami Miller School of Medicine and Holtz Children’s Hospital, Jackson Health System, Miami, FL 33136, USA
- Division of Genetics and Genomics and The Manton Center for Orphan Disease Research, Boston, MA 02115, USA
| | - Bilal Alwattar
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School; Boston, MA 02115, USA
| | - Qifei Li
- Division of Neonatology, Department of Pediatrics, University of Miami Miller School of Medicine and Holtz Children’s Hospital, Jackson Health System, Miami, FL 33136, USA
- Division of Genetics and Genomics and The Manton Center for Orphan Disease Research, Boston, MA 02115, USA
| | - Kiran Bora
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School; Boston, MA 02115, USA
| | - Alexandra K. Blomfield
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School; Boston, MA 02115, USA
| | - Jasmine Lin
- Division of Genetics and Genomics and The Manton Center for Orphan Disease Research, Boston, MA 02115, USA
| | - Anne Fulton
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School; Boston, MA 02115, USA
| | - Jing Chen
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School; Boston, MA 02115, USA
| | - Pankaj B. Agrawal
- Division of Neonatology, Department of Pediatrics, University of Miami Miller School of Medicine and Holtz Children’s Hospital, Jackson Health System, Miami, FL 33136, USA
- Division of Genetics and Genomics and The Manton Center for Orphan Disease Research, Boston, MA 02115, USA
| |
Collapse
|
8
|
Barry AM, Zhao N, Yang X, Bennett DL, Baskozos G. Deep RNA-seq of male and female murine sensory neuron subtypes after nerve injury. Pain 2023; 164:2196-2215. [PMID: 37318015 PMCID: PMC10502896 DOI: 10.1097/j.pain.0000000000002934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/27/2023] [Accepted: 02/05/2023] [Indexed: 06/16/2023]
Abstract
ABSTRACT Dorsal root ganglia (DRG) neurons have been well described for their role in driving both acute and chronic pain. Although nerve injury is known to cause transcriptional dysregulation, how this differs across neuronal subtypes and the impact of sex is unclear. Here, we study the deep transcriptional profiles of multiple murine DRG populations in early and late pain states while considering sex. We have exploited currently available transgenics to label numerous subpopulations for fluorescent-activated cell sorting and subsequent transcriptomic analysis. Using bulk tissue samples, we are able to circumvent the issues of low transcript coverage and drop-outs seen with single-cell data sets. This increases our power to detect novel and even subtle changes in gene expression within neuronal subtypes and discuss sexual dimorphism at the neuronal subtype level. We have curated this resource into an accessible database for other researchers ( https://livedataoxford.shinyapps.io/drg-directory/ ). We see both stereotyped and unique subtype signatures in injured states after nerve injury at both an early and late timepoint. Although all populations contribute to a general injury signature, subtype enrichment changes can also be seen. Within populations, there is not a strong intersection of sex and injury, but previously unknown sex differences in naïve states-particularly in Aβ-RA + Aδ-low threshold mechanoreceptors-still contribute to differences in injured neurons.
Collapse
Affiliation(s)
- Allison M. Barry
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Na Zhao
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Xun Yang
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - David L. Bennett
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Georgios Baskozos
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
9
|
Shlykov MA, Giles EM, Kelly MP, Lin SJ, Pham VT, Saccone NL, Yanik EL. Evaluation of Genetic and Nongenetic Risk Factors for Degenerative Cervical Myelopathy. Spine (Phila Pa 1976) 2023; 48:1117-1126. [PMID: 37249397 PMCID: PMC10524420 DOI: 10.1097/brs.0000000000004735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/15/2023] [Indexed: 05/31/2023]
Abstract
STUDY DESIGN Cohort study. OBJECTIVE We aimed to evaluate the associations of genetic and nongenetic factors with degenerative cervical myelopathy (DCM). SUMMARY OF BACKGROUND DATA There is mounting evidence for an inherited predisposition for DCM, but uncertainty remains regarding specific genetic markers involved. Similarly, nongenetic factors are thought to play a role. MATERIALS AND METHODS Using diagnosis codes from hospital records linked to the UK Biobank cohort, patients with cervical spondylosis were identified followed by the identification of a subset with DCM. Nongenetic variables evaluated included age, sex, race, Townsend deprivation index, body mass index, occupational demands, osteoporosis, and smoking. Genome-wide association analyses were conducted using logistic regression adjusted for age, sex, population principal components, and follow-up. RESULTS A total of 851 DCM cases out of 2787 cervical spondylosis patients were identified. Several nongenetic factors were independently associated with DCM including age [odds ratio (OR)=1.11, 95% CI=1.01-1.21, P =0.024], male sex (OR=1.63, 95% CI=1.37-1.93, P <0.001), and relative socioeconomic deprivation (OR=1.03, 95% CI=1.00-1.06, P =0.030). Asian race was associated with lower DCM risk (OR=0.44, 95% CI=0.22-0.85, P =0.014). We did not identify genome-wide significant (≤5×10 -8 ) single-nucleotide polymorphisms (SNPs) associated with DCM. The strongest genome-wide signals were at SNP rs67256809 in the intergenic region of the genes LINC02582 and FBXO15 on chromosome 18 ( P =1.12×10 -7 ) and rs577081672 in the GTPBP1 gene on chromosome 22 ( P =2.9×10 -7 ). No SNPs reported in prior DCM studies were significant after adjusting for replication attempts. CONCLUSIONS Increasing age, male sex, and relative socioeconomic deprivation were identified as independent risk factors for DCM, whereas Asian race was inversely associated. SNPs of potential interest were identified in GTPBP1 and an intergenic region on chromosome 18, but these associations did not reach genome-wide significance. Identification of genetic and nongenetic DCM susceptibility markers may guide understanding of DCM disease processes, inform risk, guide prevention and potentially inform surgical outcomes. LEVEL OF EVIDENCE Prognostic level III.
Collapse
Affiliation(s)
| | | | | | - Shiow J Lin
- Department of Genetics, Washington University School of Medicine, St. Louis, MO
| | | | - Nancy L Saccone
- Department of Genetics, Washington University School of Medicine, St. Louis, MO
| | | |
Collapse
|
10
|
Viera Ortiz AP, Cajka G, Olatunji OA, Mikytuck B, Shalem O, Lee EB. Impaired ribosome-associated quality control of C9orf72 arginine-rich dipeptide-repeat proteins. Brain 2023; 146:2897-2912. [PMID: 36516294 PMCID: PMC10316761 DOI: 10.1093/brain/awac479] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 11/05/2022] [Accepted: 12/06/2022] [Indexed: 12/15/2022] Open
Abstract
Protein quality control pathways have evolved to ensure the fidelity of protein synthesis and efficiently clear potentially toxic protein species. Defects in ribosome-associated quality control and its associated factors have been implicated in the accumulation of aberrant proteins and neurodegeneration. C9orf72 repeat-associated non-AUG translation has been suggested to involve inefficient translation elongation, lead to ribosomal pausing and activation of ribosome-associated quality control pathways. However, the role of the ribosome-associated quality control complex in the processing of proteins generated through this non-canonical translation is not well understood. Here we use reporter constructs containing the C9orf72-associated hexanucleotide repeat, ribosome-associated quality control complex deficient cell models and stain for ribosome-associated quality control markers in C9orf72-expansion carrier human tissue to understand its role in dipeptide-repeat protein pathology. Our studies show that canonical ribosome-associated quality control substrates products are efficiently cleared by the ribosome-associated quality control complex in mammalian cells. Furthermore, using stalling reporter constructs, we show that repeats associated with the C9orf72-expansion induce ribosomal stalling when arginine (R)-rich dipeptide-repeat proteins are synthesized in a length-dependent manner. However, despite triggering this pathway, these arginine-rich dipeptide-repeat proteins are not efficiently processed by the core components of the ribosome-associated quality control complex (listerin, nuclear-export mediator factor and valosin containing protein) partly due to lack of lysine residues, which precludes ubiquitination. Deficient processing by this complex may be implicated in C9orf72-expansion associated disease as dipeptide-repeat protein inclusions were observed to be predominantly devoid of ubiquitin and co-localize with nuclear-export mediator factor in mutation carriers' frontal cortex and cerebellum tissue. These findings suggest that impaired processing of these arginine-rich dipeptide-repeat proteins derived from repeat-associated non-AUG translation by the ribosome-associated quality control complex may contribute to protein homeostasis dysregulation observed in C9orf72-expansion amyotrophic lateral sclerosis and frontotemporal degeneration neuropathogenesis.
Collapse
Affiliation(s)
- Ashley P Viera Ortiz
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gregory Cajka
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Olamide A Olatunji
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bailey Mikytuck
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ophir Shalem
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Edward B Lee
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| |
Collapse
|
11
|
Storkebaum E, Rosenblum K, Sonenberg N. Messenger RNA Translation Defects in Neurodegenerative Diseases. N Engl J Med 2023; 388:1015-1030. [PMID: 36920757 DOI: 10.1056/nejmra2215795] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Affiliation(s)
- Erik Storkebaum
- From the Molecular Neurobiology Laboratory, Donders Center for Neuroscience, Donders Institute for Brain, Cognition, and Behavior, and the Faculty of Science, Radboud University, Nijmegen, the Netherlands (E.S.); the Sagol Department of Neurobiology, Faculty of Natural Sciences, and the Center for Genetic Manipulation in the Brain, University of Haifa, Haifa, Israel (K.R.); and the Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal (N.S.)
| | - Kobi Rosenblum
- From the Molecular Neurobiology Laboratory, Donders Center for Neuroscience, Donders Institute for Brain, Cognition, and Behavior, and the Faculty of Science, Radboud University, Nijmegen, the Netherlands (E.S.); the Sagol Department of Neurobiology, Faculty of Natural Sciences, and the Center for Genetic Manipulation in the Brain, University of Haifa, Haifa, Israel (K.R.); and the Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal (N.S.)
| | - Nahum Sonenberg
- From the Molecular Neurobiology Laboratory, Donders Center for Neuroscience, Donders Institute for Brain, Cognition, and Behavior, and the Faculty of Science, Radboud University, Nijmegen, the Netherlands (E.S.); the Sagol Department of Neurobiology, Faculty of Natural Sciences, and the Center for Genetic Manipulation in the Brain, University of Haifa, Haifa, Israel (K.R.); and the Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal (N.S.)
| |
Collapse
|
12
|
Eisenack TJ, Trentini DB. Ending a bad start: Triggers and mechanisms of co-translational protein degradation. Front Mol Biosci 2023; 9:1089825. [PMID: 36660423 PMCID: PMC9846516 DOI: 10.3389/fmolb.2022.1089825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 12/15/2022] [Indexed: 01/05/2023] Open
Abstract
Proteins are versatile molecular machines that control and execute virtually all cellular processes. They are synthesized in a multilayered process requiring transfer of information from DNA to RNA and finally into polypeptide, with many opportunities for error. In addition, nascent proteins must successfully navigate a complex folding-energy landscape, in which their functional native state represents one of many possible outcomes. Consequently, newly synthesized proteins are at increased risk of misfolding and toxic aggregation. To maintain proteostasis-the state of proteome balance-cells employ a plethora of molecular chaperones that guide proteins along a productive folding pathway and quality control factors that direct misfolded species for degradation. Achieving the correct balance between folding and degradation therefore represents a fundamental task for the proteostasis network. While many chaperones act co-translationally, protein quality control is generally considered to be a post-translational process, as the majority of proteins will only achieve their final native state once translation is completed. Nevertheless, it has been observed that proteins can be ubiquitinated during synthesis. The extent and the relevance of co-translational protein degradation, as well as the underlying molecular mechanisms, remain areas of open investigation. Recent studies made seminal advances in elucidating ribosome-associated quality control processes, and how their loss of function can lead to proteostasis failure and disease. Here, we discuss current understanding of the situations leading to the marking of nascent proteins for degradation before synthesis is completed, and the emerging quality controls pathways engaged in this task in eukaryotic cells. We also highlight the methods used to study co-translational quality control.
Collapse
Affiliation(s)
- Tom Joshua Eisenack
- University of Cologne, Faculty of Medicine, University Hospital of Cologne, Center for Molecular Medicine Cologne (CMMC), Cologne, Germany
| | - Débora Broch Trentini
- University of Cologne, Faculty of Medicine, University Hospital of Cologne, Center for Molecular Medicine Cologne (CMMC), Cologne, Germany,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany,*Correspondence: Débora Broch Trentini,
| |
Collapse
|
13
|
GTP-Binding Protein 1-Like (GTPBP1l) Regulates Vascular Patterning during Zebrafish Development. Biomedicines 2022; 10:biomedicines10123208. [PMID: 36551964 PMCID: PMC9775176 DOI: 10.3390/biomedicines10123208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/05/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
Genetic regulation of vascular patterning is not fully understood. Here, we report a novel gene, gtpbp1l (GTP-binding protein 1-like), that regulates vascular development in zebrafish. Amino acid sequence comparison and a phylogenetic study showed that gtpbp1l is conserved in vertebrates. Gtpbp1l mRNA is expressed in the vasculature during embryogenesis. Knockdown of gtpbp1l by morpholino impairs the patterning of the intersegmental vessel (ISV) and caudal vein plexus (CVP), indicating the role of gtpbp1l in vasculature. Further apoptosis assays and transgenic fish tests suggested that vascular defects in gtpbp1l morphants are not due to cell death but are likely caused by the impairment of migration and proliferation. Moreover, the altered expression of vessel markers is consistent with the vascular defects in gtpbp1l morphants. Finally, we revealed that gtpbp1l is regulated by VEGF/notch and BMP signaling. Collectively, these findings showed that gtpbp1l plays a critical role in vascular patterning during zebrafish development.
Collapse
|
14
|
Kriachkov V, Ormsby AR, Kusnadi EP, McWilliam HE, Mintern JD, Amarasinghe SL, Ritchie ME, Furic L, Hatters DM. Arginine-rich C9ORF72 ALS proteins stall ribosomes in a manner distinct from a canonical ribosome-associated quality control substrate. J Biol Chem 2022; 299:102774. [PMID: 36481270 PMCID: PMC9830226 DOI: 10.1016/j.jbc.2022.102774] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 11/23/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022] Open
Abstract
Hexanucleotide expansion mutations in C9ORF72 are a frequent cause of amyotrophic lateral sclerosis. We previously reported that long arginine-rich dipeptide repeats (DPRs), mimicking abnormal proteins expressed from the hexanucleotide expansion, caused translation stalling when expressed in cell culture models. Whether this stalling provides a mechanism of pathogenicity remains to be determined. Here, we explored the molecular features of DPR-induced stalling and examined whether known mechanisms such as ribosome quality control (RQC) regulate translation elongation on sequences that encode arginine-rich DPRs. We demonstrate that arginine-rich DPRs lead to stalling in a length-dependent manner, with lengths longer than 40 repeats invoking severe translation arrest. Mutational screening of 40×Gly-Xxx DPRs shows that stalling is most pronounced when Xxx is a charged amino acid (Arg, Lys, Glu, or Asp). Through a genome-wide knockout screen, we find that genes regulating stalling on polyadenosine mRNA coding for poly-Lys, a canonical RQC substrate, act differently in the case of arginine-rich DPRs. Indeed, these findings point to a limited scope for natural regulatory responses to resolve the arginine-rich DPR stalls, even though the stalls may be sensed, as evidenced by an upregulation of RQC gene expression. These findings therefore implicate arginine-rich DPR-mediated stalled ribosomes as a source of stress and toxicity and may be a crucial component in pathomechanisms.
Collapse
Affiliation(s)
- Viacheslav Kriachkov
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Angelique R. Ormsby
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Eric P. Kusnadi
- Translational Prostate Cancer Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
| | - Hamish E.G. McWilliam
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia,Department of Microbiology and Immunology, Peter Doherty Institute of Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Justine D. Mintern
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | | | - Matthew E. Ritchie
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
| | - Luc Furic
- Translational Prostate Cancer Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia,Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute Cancer Program, Monash University, Clayton, Victoria, Australia
| | - Danny M. Hatters
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia,For correspondence: Danny M. Hatters
| |
Collapse
|
15
|
Proteostasis Deregulation in Neurodegeneration and Its Link with Stress Granules: Focus on the Scaffold and Ribosomal Protein RACK1. Cells 2022; 11:cells11162590. [PMID: 36010666 PMCID: PMC9406587 DOI: 10.3390/cells11162590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/09/2022] [Accepted: 08/17/2022] [Indexed: 12/12/2022] Open
Abstract
The role of protein misfolding, deposition, and clearance has been the dominant topic in the last decades of investigation in the field of neurodegeneration. The impairment of protein synthesis, along with RNA metabolism and RNA granules, however, are significantly emerging as novel potential targets for the comprehension of the molecular events leading to neuronal deficits. Indeed, defects in ribosome activity, ribosome stalling, and PQC—all ribosome-related processes required for proteostasis regulation—can contribute to triggering stress conditions and promoting the formation of stress granules (SGs) that could evolve in the formation of pathological granules, usually occurring during neurodegenerating effects. In this review, the interplay between proteostasis, mRNA metabolism, and SGs has been explored in a neurodegenerative context with a focus on Alzheimer’s disease (AD), although some defects in these same mechanisms can also be found in frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), which are discussed here. Finally, we highlight the role of the receptor for activated C kinase 1 (RACK1) in these pathologies and note that, besides its well characterized function as a scaffold protein, it has an important role in translation and can associate to stress granules (SGs) determining cell fate in response to diverse stress stimuli.
Collapse
|
16
|
Inducible Systemic Gcn1 Deletion in Mice Leads to Transient Body Weight Loss upon Tamoxifen Treatment Associated with Decrease of Fat and Liver Glycogen Storage. Int J Mol Sci 2022; 23:ijms23063201. [PMID: 35328622 PMCID: PMC8949040 DOI: 10.3390/ijms23063201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/09/2022] [Accepted: 03/15/2022] [Indexed: 02/06/2023] Open
Abstract
GCN1 is an evolutionarily-conserved ribosome-binding protein that mediates the amino acid starvation response as well as the ribotoxic stress response. We previously demonstrated that Gcn1 mutant mice lacking the GCN2-binding domain suffer from growth retardation and postnatal lethality via GCN2-independent mechanisms, while Gcn1-null mice die early in embryonic development. In this study, we explored the role of GCN1 in adult mice by generating tamoxifen-inducible conditional knockout (CKO) mice. Unexpectedly, the Gcn1 CKO mice showed body weight loss during tamoxifen treatment, which gradually recovered following its cessation. They also showed decreases in liver weight, hepatic glycogen and lipid contents, blood glucose and non-esterified fatty acids, and visceral white adipose tissue weight with no changes in food intake and viability. A decrease of serum VLDL suggested that hepatic lipid supply to the peripheral tissues was primarily impaired. Liver proteomic analysis revealed the downregulation of mitochondrial β-oxidation that accompanied increases of peroxisomal β-oxidation and aerobic glucose catabolism that maintain ATP levels. These findings show the involvement of GCN1 in hepatic lipid metabolism during tamoxifen treatment in adult mice.
Collapse
|
17
|
Lai LB, Lai SM, Szymanski ES, Kapur M, Choi EK, Al-Hashimi HM, Ackerman SL, Gopalan V. Structural basis for impaired 5' processing of a mutant tRNA associated with defects in neuronal homeostasis. Proc Natl Acad Sci U S A 2022; 119:e2119529119. [PMID: 35238631 PMCID: PMC8915964 DOI: 10.1073/pnas.2119529119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/09/2022] [Indexed: 02/06/2023] Open
Abstract
SignificanceUnderstanding and treating neurological disorders are global priorities. Some of these diseases are engendered by mutations that cause defects in the cellular synthesis of transfer RNAs (tRNAs), which function as adapter molecules that translate messenger RNAs into proteins. During tRNA biogenesis, ribonuclease P catalyzes removal of the transcribed sequence upstream of the mature tRNA. Here, we focus on a cytoplasmic tRNAArgUCU that is expressed specifically in neurons and, when harboring a particular point mutation, contributes to neurodegeneration in mice. Our results suggest that this mutation favors stable alternative structures that are not cleaved by mouse ribonuclease P and motivate a paradigm that may help to understand the molecular basis for disease-associated mutations in other tRNAs.
Collapse
Affiliation(s)
- Lien B. Lai
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Stella M. Lai
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Eric S. Szymanski
- Department of Biochemistry, School of Medicine, Duke University, Durham, NC 27710
| | - Mridu Kapur
- Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California San Diego, La Jolla, CA 92093
- Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA 92093
| | - Edric K. Choi
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| | - Hashim M. Al-Hashimi
- Department of Biochemistry, School of Medicine, Duke University, Durham, NC 27710
| | - Susan L. Ackerman
- Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California San Diego, La Jolla, CA 92093
- Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA 92093
| | - Venkat Gopalan
- Department of Chemistry & Biochemistry, The Ohio State University, Columbus, OH 43210
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210
| |
Collapse
|
18
|
Young DJ, Guydosh NR. Rebirth of the translational machinery: The importance of recycling ribosomes. Bioessays 2022; 44:e2100269. [PMID: 35147231 PMCID: PMC9270684 DOI: 10.1002/bies.202100269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 11/10/2022]
Abstract
Translation of the genetic code occurs in a cycle where ribosomes engage mRNAs, synthesize protein, and then disengage in order to repeat the process again. The final part of this process-ribosome recycling, where ribosomes dissociate from mRNAs-involves a complex molecular choreography of specific protein factors to remove the large and small subunits of the ribosome in a coordinated fashion. Errors in this process can lead to the accumulation of ribosomes at stop codons or translation of downstream open reading frames (ORFs). Ribosome recycling is also critical when a ribosome stalls during the elongation phase of translation and must be rescued to allow continued translation of the mRNA. Here we discuss the molecular interactions that drive ribosome recycling, and their regulation in the cell. We also examine the consequences of inefficient recycling with regards to disease, and its functional roles in synthesis of novel peptides, regulation of gene expression, and control of mRNA-associated proteins. Alterations in ribosome recycling efficiency have the potential to impact many cellular functions but additional work is needed to understand how this regulatory power is utilized.
Collapse
Affiliation(s)
- David J Young
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Nicholas R Guydosh
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| |
Collapse
|
19
|
Eastman G, Sharlow ER, Lazo JS, Bloom GS, Sotelo-Silveira JR. Transcriptome and Translatome Regulation of Pathogenesis in Alzheimer's Disease Model Mice. J Alzheimers Dis 2022; 86:365-386. [PMID: 35034904 DOI: 10.3233/jad-215357] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Defining cellular mechanisms that drive Alzheimer's disease (AD) pathogenesis and progression will be aided by studies defining how gene expression patterns change during pre-symptomatic AD and ensuing periods of declining cognition. Previous studies have emphasized changes in transcriptome, but not translatome regulation, leaving the ultimate results of gene expression alterations relatively unexplored in the context of AD. OBJECTIVE To identify genes whose expression might be regulated at the transcriptome and translatome levels in AD, we analyzed gene expression in cerebral cortex of two AD model mouse strains, CVN (APPSwDI;NOS2 -/- ) and Tg2576 (APPSw), and their companion wild type (WT) strains at 6 months of age by tandem RNA-Seq and Ribo-Seq (ribosome profiling). METHODS Identical starting pools of bulk RNA were used for RNA-Seq and Ribo-Seq. Differential gene expression analysis was performed at the transcriptome, translatome, and translational efficiency levels. Regulated genes were functionally evaluated by gene ontology tools. RESULTS Compared to WT mice, AD model mice had similar levels of transcriptome regulation, but differences in translatome regulation. A microglial signature associated with early stages of Aβ accumulation was upregulated at both levels in CVN mice. Although the two mice strains did not share many regulated genes, they showed common regulated pathways related to AβPP metabolism associated with neurotoxicity and neuroprotection. CONCLUSION This work represents the first genome-wide study of brain translatome regulation in animal models of AD and provides evidence of a tight and early translatome regulation of gene expression controlling the balance between neuroprotective and neurodegenerative processes in brain.
Collapse
Affiliation(s)
- Guillermo Eastman
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Ministerio de Educación y Cultura, Montevideo, Uruguay.,Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Elizabeth R Sharlow
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - John S Lazo
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.,Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - George S Bloom
- Department of Biology, University of Virginia, Charlottesville, VA, USA.,Department of Cell Biology, University of Virginia, Charlottesville, VA, USA.,Department of Neuroscience, University of Virginia, Charlottesville, VA, USA
| | - José R Sotelo-Silveira
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Ministerio de Educación y Cultura, Montevideo, Uruguay.,Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| |
Collapse
|
20
|
Park J, Park J, Lee J, Lim C. The trinity of ribosome-associated quality control and stress signaling for proteostasis and neuronal physiology. BMB Rep 2021. [PMID: 34488933 PMCID: PMC8505234 DOI: 10.5483/bmbrep.2021.54.9.097] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Translating ribosomes accompany co-translational regulation of nascent polypeptide chains, including subcellular targeting, protein folding, and covalent modifications. Ribosome-associated quality control (RQC) is a co-translational surveillance mechanism triggered by ribosomal collisions, an indication of atypical translation. The ribosome-associated E3 ligase ZNF598 ubiquitinates small subunit proteins at the stalled ribosomes. A series of RQC factors are then recruited to dissociate and triage aberrant translation intermediates. Regulatory ribosomal stalling may occur on endogenous transcripts for quality gene expression, whereas ribosomal collisions are more globally induced by ribotoxic stressors such as translation inhibitors, ribotoxins, and UV radiation. The latter are sensed by ribosome-associated kinases GCN2 and ZAKα, activating integrated stress response (ISR) and ribotoxic stress response (RSR), respectively. Hierarchical crosstalks among RQC, ISR, and RSR pathways are readily detectable since the collided ribosome is their common substrate for activation. Given the strong implications of RQC factors in neuronal physiology and neurological disorders, the interplay between RQC and ribosome-associated stress signaling may sustain proteostasis, adaptively determine cell fate, and contribute to neural pathogenesis. The elucidation of underlying molecular principles in relevant human diseases should thus provide unexplored therapeutic opportunities.
Collapse
Affiliation(s)
- Jumin Park
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Jongmin Park
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Jongbin Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Chunghun Lim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| |
Collapse
|
21
|
English AM, Green KM, Moon SL. A (dis)integrated stress response: Genetic diseases of eIF2α regulators. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1689. [PMID: 34463036 DOI: 10.1002/wrna.1689] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 01/28/2023]
Abstract
The integrated stress response (ISR) is a conserved mechanism by which eukaryotic cells remodel gene expression to adapt to intrinsic and extrinsic stressors rapidly and reversibly. The ISR is initiated when stress-activated protein kinases phosphorylate the major translation initiation factor eukaryotic translation initiation factor 2ɑ (eIF2ɑ), which globally suppresses translation initiation activity and permits the selective translation of stress-induced genes including important transcription factors such as activating transcription factor 4 (ATF4). Translationally repressed messenger RNAs (mRNAs) and noncoding RNAs assemble into cytoplasmic RNA-protein granules and polyadenylated RNAs are concomitantly stabilized. Thus, regulated changes in mRNA translation, stability, and localization to RNA-protein granules contribute to the reprogramming of gene expression that defines the ISR. We discuss fundamental mechanisms of RNA regulation during the ISR and provide an overview of a growing class of genetic disorders associated with mutant alleles of key translation factors in the ISR pathway. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA in Disease and Development > RNA in Disease Translation > Translation Regulation RNA in Disease and Development > RNA in Development.
Collapse
Affiliation(s)
- Alyssa M English
- Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Katelyn M Green
- Department of Chemistry, Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Stephanie L Moon
- Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
| |
Collapse
|
22
|
Padmanabhan PK, Ferreira GR, Zghidi-Abouzid O, Oliveira C, Dumas C, Mariz FC, Papadopoulou B. Genetic depletion of the RNA helicase DDX3 leads to impaired elongation of translating ribosomes triggering co-translational quality control of newly synthesized polypeptides. Nucleic Acids Res 2021; 49:9459-9478. [PMID: 34358325 PMCID: PMC8450092 DOI: 10.1093/nar/gkab667] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 07/15/2021] [Accepted: 07/23/2021] [Indexed: 11/29/2022] Open
Abstract
DDX3 is a multifaceted RNA helicase of the DEAD-box family that plays central roles in all aspects of RNA metabolism including translation initiation. Here, we provide evidence that the Leishmania DDX3 ortholog functions in post-initiation steps of translation. We show that genetic depletion of DDX3 slows down ribosome movement resulting in elongation-stalled ribosomes, impaired translation elongation and decreased de novo protein synthesis. We also demonstrate that the essential ribosome recycling factor Rli1/ABCE1 and termination factors eRF3 and GTPBP1 are less recruited to ribosomes upon DDX3 loss, suggesting that arrested ribosomes may be inefficiently dissociated and recycled. Furthermore, we show that prolonged ribosome stalling triggers co-translational ubiquitination of nascent polypeptide chains and a higher recruitment of E3 ubiquitin ligases and proteasome components to ribosomes of DDX3 knockout cells, which further supports that ribosomes are not elongating optimally. Impaired elongation of translating ribosomes also results in the accumulation of cytoplasmic protein aggregates, which implies that defects in translation overwhelm the normal quality controls. The partial recovery of translation by overexpressing Hsp70 supports this possibility. Collectively, these results suggest an important novel contribution of DDX3 to optimal elongation of translating ribosomes by preventing prolonged translation stalls and stimulating recycling of arrested ribosomes.
Collapse
Affiliation(s)
- Prasad Kottayil Padmanabhan
- Research Center in Infectious Diseases, Division of Infectious Disease and Immunity CHU de Quebec Research Center-University Laval, Quebec, QC G1V 4G2, Canada.,Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC G1V 4G2, Canada
| | - Gabriel Reis Ferreira
- Research Center in Infectious Diseases, Division of Infectious Disease and Immunity CHU de Quebec Research Center-University Laval, Quebec, QC G1V 4G2, Canada.,Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC G1V 4G2, Canada
| | - Ouafa Zghidi-Abouzid
- Research Center in Infectious Diseases, Division of Infectious Disease and Immunity CHU de Quebec Research Center-University Laval, Quebec, QC G1V 4G2, Canada.,Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC G1V 4G2, Canada
| | - Camila Oliveira
- Research Center in Infectious Diseases, Division of Infectious Disease and Immunity CHU de Quebec Research Center-University Laval, Quebec, QC G1V 4G2, Canada.,Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC G1V 4G2, Canada
| | - Carole Dumas
- Research Center in Infectious Diseases, Division of Infectious Disease and Immunity CHU de Quebec Research Center-University Laval, Quebec, QC G1V 4G2, Canada.,Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC G1V 4G2, Canada
| | - Filipe Colaço Mariz
- Research Center in Infectious Diseases, Division of Infectious Disease and Immunity CHU de Quebec Research Center-University Laval, Quebec, QC G1V 4G2, Canada.,Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC G1V 4G2, Canada
| | - Barbara Papadopoulou
- Research Center in Infectious Diseases, Division of Infectious Disease and Immunity CHU de Quebec Research Center-University Laval, Quebec, QC G1V 4G2, Canada.,Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC G1V 4G2, Canada
| |
Collapse
|
23
|
Lata E, Choquet K, Sagliocco F, Brais B, Bernard G, Teichmann M. RNA Polymerase III Subunit Mutations in Genetic Diseases. Front Mol Biosci 2021; 8:696438. [PMID: 34395528 PMCID: PMC8362101 DOI: 10.3389/fmolb.2021.696438] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/21/2021] [Indexed: 12/24/2022] Open
Abstract
RNA polymerase (Pol) III transcribes small untranslated RNAs such as 5S ribosomal RNA, transfer RNAs, and U6 small nuclear RNA. Because of the functions of these RNAs, Pol III transcription is best known for its essential contribution to RNA maturation and translation. Surprisingly, it was discovered in the last decade that various inherited mutations in genes encoding nine distinct subunits of Pol III cause tissue-specific diseases rather than a general failure of all vital functions. Mutations in the POLR3A, POLR3C, POLR3E and POLR3F subunits are associated with susceptibility to varicella zoster virus-induced encephalitis and pneumonitis. In addition, an ever-increasing number of distinct mutations in the POLR3A, POLR3B, POLR1C and POLR3K subunits cause a spectrum of neurodegenerative diseases, which includes most notably hypomyelinating leukodystrophy. Furthermore, other rare diseases are also associated with mutations in genes encoding subunits of Pol III (POLR3H, POLR3GL) and the BRF1 component of the TFIIIB transcription initiation factor. Although the causal relationship between these mutations and disease development is widely accepted, the exact molecular mechanisms underlying disease pathogenesis remain enigmatic. Here, we review the current knowledge on the functional impact of specific mutations, possible Pol III-related disease-causing mechanisms, and animal models that may help to better understand the links between Pol III mutations and disease.
Collapse
Affiliation(s)
- Elisabeth Lata
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
| | - Karine Choquet
- Department of Genetics, Harvard Medical School, Boston, MA, United States
| | - Francis Sagliocco
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
| | - Bernard Brais
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Geneviève Bernard
- Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Martin Teichmann
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
| |
Collapse
|
24
|
Yip MCJ, Shao S. Detecting and Rescuing Stalled Ribosomes. Trends Biochem Sci 2021; 46:731-743. [PMID: 33966939 DOI: 10.1016/j.tibs.2021.03.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/18/2021] [Accepted: 03/30/2021] [Indexed: 11/24/2022]
Abstract
Ribosomes that stall inappropriately during protein synthesis harbor proteotoxic components linked to cellular stress and neurodegenerative diseases. Molecular mechanisms that rescue stalled ribosomes must selectively detect rare aberrant translational complexes and process the heterogeneous components. Ribosome-associated quality control pathways eliminate problematic messenger RNAs and nascent proteins on stalled translational complexes. In addition, recent studies have uncovered general principles of stall recognition upstream of quality control pathways and fail-safe mechanisms that ensure nascent proteome integrity. Here, we discuss developments in our mechanistic understanding of the detection and rescue of stalled ribosomal complexes in eukaryotes.
Collapse
Affiliation(s)
- Matthew C J Yip
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
| | - Sichen Shao
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
| |
Collapse
|
25
|
Terrey M, Adamson SI, Chuang JH, Ackerman SL. Defects in translation-dependent quality control pathways lead to convergent molecular and neurodevelopmental pathology. eLife 2021; 10:e66904. [PMID: 33899734 PMCID: PMC8075583 DOI: 10.7554/elife.66904] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/05/2021] [Indexed: 12/27/2022] Open
Abstract
Translation-dependent quality control pathways such as no-go decay (NGD), non-stop decay (NSD), and nonsense-mediated decay (NMD) govern protein synthesis and proteostasis by resolving non-translating ribosomes and preventing the production of potentially toxic peptides derived from faulty and aberrant mRNAs. However, how translation is altered and the in vivo defects that arise in the absence of these pathways are poorly understood. Here, we show that the NGD/NSD factors Pelo and Hbs1l are critical in mice for cerebellar neurogenesis but expendable for survival of these neurons after development. Analysis of mutant mouse embryonic fibroblasts revealed translational pauses, alteration of signaling pathways, and translational reprogramming. Similar effects on signaling pathways, including mTOR activation, the translatome and mouse cerebellar development were observed upon deletion of the NMD factor Upf2. Our data reveal that these quality control pathways that function to mitigate errors at distinct steps in translation can evoke similar cellular responses.
Collapse
Affiliation(s)
- Markus Terrey
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, Division of Biological Sciences, University of California San DiegoLa JollaUnited States
- Graduate School of Biomedical Sciences and Engineering, University of MaineOronoUnited States
| | - Scott I Adamson
- The Jackson Laboratory for Genomic MedicineFarmingtonUnited States
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn HealthFarmingtonUnited States
| | - Jeffrey H Chuang
- The Jackson Laboratory for Genomic MedicineFarmingtonUnited States
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn HealthFarmingtonUnited States
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, Division of Biological Sciences, University of California San DiegoLa JollaUnited States
| |
Collapse
|
26
|
Terrey M, Adamson SI, Gibson AL, Deng T, Ishimura R, Chuang JH, Ackerman SL. GTPBP1 resolves paused ribosomes to maintain neuronal homeostasis. eLife 2020; 9:e62731. [PMID: 33186095 PMCID: PMC7665888 DOI: 10.7554/elife.62731] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 10/26/2020] [Indexed: 12/14/2022] Open
Abstract
Ribosome-associated quality control pathways respond to defects in translational elongation to recycle arrested ribosomes and degrade aberrant polypeptides and mRNAs. Loss of a tRNA gene leads to ribosomal pausing that is resolved by the translational GTPase GTPBP2, and in its absence causes neuron death. Here, we show that loss of the homologous protein GTPBP1 during tRNA deficiency in the mouse brain also leads to codon-specific ribosome pausing and neurodegeneration, suggesting that these non-redundant GTPases function in the same pathway to mitigate ribosome pausing. As observed in Gtpbp2-/- mice (Ishimura et al., 2016), GCN2-mediated activation of the integrated stress response (ISR) was apparent in the Gtpbp1-/- brain. We observed decreased mTORC1 signaling which increased neuronal death, whereas ISR activation was neuroprotective. Our data demonstrate that GTPBP1 functions as an important quality control mechanism during translation elongation and suggest that translational signaling pathways intricately interact to regulate neuronal homeostasis during defective elongation.
Collapse
Affiliation(s)
- Markus Terrey
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, Division of Biological Sciences, University of California, San DiegoSan DiegoUnited States
- Graduate School of Biomedical Sciences and Engineering, University of MaineOronoUnited States
| | - Scott I Adamson
- The Jackson Laboratory for Genomic MedicineFarmingtonUnited States
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, UConn HealthFarmingtonUnited States
| | - Alana L Gibson
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, Division of Biological Sciences, University of California, San DiegoSan DiegoUnited States
| | - Tianda Deng
- Division of Biological Sciences, Section of Molecular Biology, University of California, San DiegoSan DiegoUnited States
| | - Ryuta Ishimura
- The Jackson Laboratory for Mammalian GeneticsBar HarborUnited States
| | - Jeffrey H Chuang
- The Jackson Laboratory for Genomic MedicineFarmingtonUnited States
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, Division of Biological Sciences, University of California, San DiegoSan DiegoUnited States
| |
Collapse
|